Despite a bystander's offer to call police, the men put the injured man back in the truck and drove off.

About 13 hours later, Leon's body turned up in some weeds on the shoulder of I-95 in Lake Worth - four miles from the place where he suffered the fatal injury. His companions told authorities that after the fall, Leon wanted to walk, so they let him out.

But an autopsy on Monday showed Leon would have been either comatose or dead seconds after he hit the pavement.

"He could never, ever, ever regain consciousness," medical examiner's investigator Sam Altschul said of Leon's injuries. "He would have gone into an immediate coma and remained in the coma until death."

Altschul said the autopsy could not determine exactly when Leon died.

"Was he dead at the moment they dumped him? There's no way to tell," he said.

The death left investigators with a troubling puzzle.

"This is a strange situation," FHP Lt. Roy Rogers said. "The whole thing is rather bizarre, to say the least."

Rogers said the witness tailed the truck with the three men inside to a Lantana home. Duke and Raul Leon got out of the truck and began to fight. The witness called 911, but the men left in the truck before Palm Beach County sheriff's deputies arrived.

The witness gave deputies the license plate number, which helped them trace the truck to Raul Leon's Delray Beach home.

Sergio Leon's body was subsequently left near the 10th Avenue North interstate exit ramp in Lake Worth. Acting on information that Leon was walking along the highway, troopers and deputies searched for him, but it turned out they were looking too far south, Rogers said.

A passing motorist noticed the body on Sunday.

"We don't know exactly why they put him there," Rogers said.

Rogers said FHP traffic homicide investigators will complete witness interviews in the next two weeks and hand the case over to the State Attorney's Office for possible criminal charges.

Raul Leon could not be reached for comment on Monday. A woman who answered the phone at his home said he did not want to talk and hung up. Duke also could not be reached for comment.